feat: look at alternative tracks for streaming

Author: devgianlu

player.go

@@ -32,6 +32,14 @@ func NewMediaFromEpisode(episode *metadatapb.Episode) *Media {
 	return &Media{track: nil, episode: episode}
 }
 
+func (te Media) Id() SpotifyId {
+	if te.track != nil {
+		return SpotifyIdFromGid(SpotifyIdTypeTrack, te.track.GetGid())
+	} else {
+		return SpotifyIdFromGid(SpotifyIdTypeEpisode, te.episode.GetGid())
+	}
+}
+
 func (te Media) IsTrack() bool {
 	return te.track != nil
 }

player/player.go

@@ -31,8 +31,6 @@ const (
 
 const MaxStateVolume = 65535
 
-const DisableCheckMediaRestricted = true
-
 const CdnUrlQuarantineDuration = 15 * time.Minute
 
 func ptr[T any](v T) *T {
@@ -539,6 +537,38 @@ func calculateNormalisationFactor(params *audiofilespb.NormalizationParams, preg
 	return normalisationFactor
 }
 
+func (p *Player) getUnrestrictedTrack(ctx context.Context, spotId librespot.SpotifyId) (*metadatapb.Track, error) {
+	var trackMeta metadatapb.Track
+	err := p.sp.ExtendedMetadataSimple(ctx, spotId, extmetadatapb.ExtensionKind_TRACK_V4, &trackMeta)
+	if err != nil {
+		return nil, fmt.Errorf("failed getting track metadata: %w", err)
+	}
+
+	media := librespot.NewMediaFromTrack(&trackMeta)
+	if !isMediaRestricted(media, *p.countryCode) {
+		return &trackMeta, nil
+	}
+
+	for _, alt := range trackMeta.Alternative {
+		media = librespot.NewMediaFromTrack(alt)
+		if !isMediaRestricted(media, *p.countryCode) {
+			// Clear alternatives to avoid confusion
+			trackMeta.Alternative = nil
+
+			// The alternative track does not have all fields set, copy them over
+			// to the original track metadata.
+			trackMeta.Gid = alt.Gid
+			trackMeta.File = alt.File
+			trackMeta.Preview = alt.Preview
+			trackMeta.OriginalAudio = alt.OriginalAudio
+			return &trackMeta, nil
+		}
+	}
+
+	// We tried all alternatives, still restricted
+	return nil, librespot.ErrMediaRestricted
+}
+
 func (p *Player) NewStream(ctx context.Context, client *http.Client, spotId librespot.SpotifyId, bitrate int, mediaPosition int64) (*Stream, error) {
 	log := p.log.WithField("uri", spotId.Uri())
 
@@ -551,16 +581,13 @@ func (p *Player) NewStream(ctx context.Context, client *http.Client, spotId libr
 	var media *librespot.Media
 	var file *metadatapb.AudioFile
 	if spotId.Type() == librespot.SpotifyIdTypeTrack {
-		var trackMeta metadatapb.Track
-		err := p.sp.ExtendedMetadataSimple(ctx, spotId, extmetadatapb.ExtensionKind_TRACK_V4, &trackMeta)
+		trackMeta, err := p.getUnrestrictedTrack(ctx, spotId)
 		if err != nil {
-			return nil, fmt.Errorf("failed getting track metadata: %w", err)
+			return nil, err
 		}
 
-		media = librespot.NewMediaFromTrack(&trackMeta)
-		if !DisableCheckMediaRestricted && isMediaRestricted(media, *p.countryCode) {
-			return nil, librespot.ErrMediaRestricted
-		}
+		media = librespot.NewMediaFromTrack(trackMeta)
+		spotId = media.Id()
 
 		var audioFilesResp audiofilespb.AudioFilesExtensionResponse
 		err = p.sp.ExtendedMetadataSimple(ctx, spotId, extmetadatapb.ExtensionKind_AUDIO_FILES, &audioFilesResp)
@@ -601,7 +628,7 @@ func (p *Player) NewStream(ctx context.Context, client *http.Client, spotId libr
 		}
 
 		media = librespot.NewMediaFromEpisode(&episodeMeta)
-		if !DisableCheckMediaRestricted && isMediaRestricted(media, *p.countryCode) {
+		if isMediaRestricted(media, *p.countryCode) {
 			return nil, librespot.ErrMediaRestricted
 		}